Originally posted by: Dman877
Originally posted by: alkemyst
I didn't do a before and after on my intake, but since adding my header, cat and exhaust my mileage has seemed to improve.
It's only been a couple tanks so far...I am continuing to watch it.
Header and exhaust will improve efficiency by reducing back pressure and power loss during the exhaust stroke. A cold air intake, as others have said, allows the engine to burn more fuel due to the denser air, thus reducing fuel economy (though I doubt the difference is even noticeable)
It depends on the exhaust. To put it simply, backpressure is a important measure of how much torque you're creating at low to mid rpms which is why all cars don't just have a 4" exhaust back from the cat.
Now horsepower is a function of torque and yes, too much low can decrease power. A equal length header followed by 4 piping with no cat on a 4 cylinder car will probably make you lose hp and torque cross the board.
If you want to create better mileage, you want more torque down low so you don't have to bring the engine as high up to get it moving and you can stay in higher gears longer.
What you're seeing is instead the switch from winter blend fuel to summer fuels. During winter months, you probably get a 85/15% blend of ethanol and gasoline, which means you're only getting 94.75% of the total energy content hat you'd get from a gallon of 100% gasoline.
As for the OP, intakes won't noticeably improve anything besides making the "whoosh" intake noise louder. Power will be affected minimally and mileage will not go anywhere in any measurable amount.
Facebook
Twitter